Money is one of the key factors for starting an online business, make sure you have sufficient enough to avoid unnecessary pressure.
Online business models are of various types, they can be a product based or user generated content based or just offering services.
Particularly for user generated content sites, that are web2.0 focused, its really important to attract the first set of visitors and later on there is every probability that they would drive others.
When it comes to revenues, other than just ad revenue, try to get some long term advertising deals that would really help to ease your financial pressure.
If feasible try to have an exclusively resource focusing on attracting revenues and other attractive ads.
It‘s absolutely advantageous to have an in-house SEO, who would not only help to increase visitors but also suggest on the ways to increase conversion rates.